Occlusion of carotid artery or air embolism in Mongolian gerbils produced changes in cerebrovascular permeability which were differential and selective in character with regard to various tracers tested. This indicates a variety of mechanisms involved in abnormal transendothelial passage. The disturbances of the BBB could not be topographically correlated either with the changes of regional CBF or with the changes in regional glucose utilization. The latter appeared in various anatomical structures indicating a wide extension of metabolic changes in cerebral ischemia. This project has been completed.